The Palm Stimulator was placed in the palm of the child's active hand 20 seconds before the injection. It ensured by researcher that the apparatus was held tightly in the child's palm throughout the procedure. The apparatus was taken back from the child after completing the injection process.

ShotBlocker was placed in the ventrogluteal area properly 20 seconds before injection. It was fixed at the injection site until the injection process was completed.

The routine IM injection was applied to the children in the control group.

The Palm Stimulator, developed by the present researchers for the first time, is 1.6 cm in diameter, 4 cm in length, and has a cylindrical, non-slippery structure for an easy grip to ensure maximum contact with the palm The Palm Stimulator consists of blunt protrusions that will provide a tactile stimulus on the palm. The blunt protrusions do not penetrate into the skin. The simulator design is based on the gate-control theory, which allows for a reduction in the perceived amount of pain experienced during injection by closing the pain gate in the spinal cord in creating a stimulus on the skin.

The Children's Fear Scale (CFS) is a scale used to assess the level of anxiety in children. The scale is a visual measurement tool with scores ranging from 0-4 points. It consists of five facial expressions, ranging from a neutral to a frightened expression, and is suitable for use with children aged 5-10 years (Inan & Inal, 2019; McMurtry, Noel, Chambers, & McGrath, 2011; Özalp Gerçeker, Ayar, Özdemir, & Bektaş, 2018). The evaluation of the Turkish psychometric properties of the scale, which was developed by McMurty et al. for paediatric patients, was conducted by Özalp Gerçeker et al. (2018), and the scale was translated into the Turkish language (Özalp Gerçeker et al., 2018). The CFS has demonstrated good evidence of test-retest (r = 0.76, p < 0.001), and inter-rater (0.51, P < 0.001) reliability, as well as construct validity, (rs ¼ when used with children (McMurtry vd., 2011).

The Faces Pain Scale-Revised (FPS) is a scale used to assess the level of pain in children in the 4-12 age group (Hicks, Von Baeyer, Spafford, Van Korlaar, & Goodenough, 2001). There are facial expressions that show the increasing levels of pain severity from left to right in the scale. Rated according to the severity of pain (between 0-10 points), the leftmost face refers to "no pain", and the rightmost face refers to "too much pain", comprising a total of six facial expressions. The faces exhibit an increase in pain severity to correspond with the scores 0, 2, 4, 6, 8, and 10 from left to right, respectively (Mohamed Mohamed Tork, 2017).

The VAS consists of a horizontal or vertical ruler 10 cm/100 mm in length, with the phrase "no pain" on one end and "the worst pain imaginable" on the other. The child is asked to mark the point on this line that most accurately reflects his/her pain. The distance between the child's mark and the left end of the scale is measured in cm and recorded as "points". It has been suggested that the widely researched scale should be used for children aged seven and older (Çelik & Khorshid, 2015; Sivri Bilgen & Balcı, 2019).